the minimum size of a nuclear reactor core or nuclear weapon that can be made critical for a specific geometrical arrangement and material composition; the critical size must at least include enough fissionable material to reach critical mass

to send from one person, thing, or place to another; convey; to cause to spread; pass on; to impart or convey to others by heredity or inheritance; hand down; to pass along (news or information); communicate

a set of statements or principles devised to explain a group of facts or phenomena, especially one that has been repeatedly tested or is widely accepted and can be used to make predictions about natural phenomena